The present invention relates to process I/O controllers for semiconductor manufacturing to which a tool host can delegate data collection, monitoring and control tasks. In particular, it relates to process I/O controllers that can perform more than one of data collection, monitoring, control and response to commands from a tool host with statistically repeatable performance and precision. Embodiments described use prioritized real time operating systems to control of semiconductor manufacturing tools and data collection from tool associated with the sensors. Statistically repeatable responsiveness to selected commands and to sensor inputs during selected recipe steps effectively reduces jitter.
Moore's law promises exponential growth in computer power at diminishing prices. This dynamic growth of processing power might lead one to think that semiconductor device manufacturing would be an adventuresome business, like wild-catting for oil. Just the opposite is true. Because manufacturing batches are very valuable and manufacturing processes are sensitive to even small mistakes, semiconductor device manufacturing is a conservative business. Qualification cycles and standards for new equipment and modifications of old equipment are lengthy and demanding. Even a small change is vetted extensively, before being released to production.
Key components used by a fab in semiconductor manufacturing include tools (e.g., deposition chambers, reactors), sensors that monitor the tools (e.g., FTIR sensors, mass spectrographs, thermocouples) and hosts or distributed processors that store and analyze data from the sensors regarding tool operation.
A prior application described a transparent method of listening to data from the sensors and providing it to the hosts or distributed processors using high speed and error-resistant technologies such as TCP/IP over Ethernet. The prior application was by inventors Uzi Lev-Ami and Yossef Ilan Reich, “Method and Apparatus for Monitoring Host to Tool Communications,” application Ser. No. 09/935,213, filed on 22 Aug. 2001, now U.S. Pat. No. 7,200,671, which is incorporated by reference. The prior application describes a listening post that could eavesdrop on serial communications from a tool or sensor using an optically isolated connector. Using the eavesdropping approach, one could prove that the fab communications and data collection infrastructure could be upgraded without requiring modification of tools or sensors, at a low risk. The upgrade feasibility could be demonstrated without dismantling the incumbent communications infrastructure.
The next revolution in fab instrumentation and backend analysis capabilities will involve adding intelligent controllers such as process I/O controllers to mediate communications between the tools and sensors, on one side of the process I/O controllers, and tool hosts or distributed processors, on the other side, without needing to replace or change the analytical characteristics of the sensors. Increased processor power and decreased storage cost create opportunities for configurations that would not previously have been practical in a fab environment. A second prior application by inventors Uzi Lev-Ami, Guenter Sifnatsch and Mark Attwood, entitled “Controller and Method to Mediate Data Collection from Smart Sensors for Fab Applications”, U.S. patent application Ser. No. 10/819,903 filed on 7 Apr. 2004, now U.S. Pat. No. 7,146,237, describes an intelligent controller with various capabilities. Lacking from the described intelligent controllers is an ability to simultaneously carry out a variety of functions, in cooperation with the tool hosts, while providing statistically repeatable responsiveness. Jitter in the time at which commands are initiated or completed is not well-controlled in current software architectures.
An opportunity arises to change the model of control applied to process chambers by delegating data collection and critical control from the tool host or distributed processor to the process I/O controller. Better, more easily configured and controlled, more resilient components and systems with statistically repeatable responsiveness may result.